The present invention relates to a disk-recording and reproducing apparatus utilizing optical storage or magneto-optical storage technology or the like, and a disk cartridge therefor.
Advance of a digital technology increases data to be processed, and media for recording and reproducing data are being developed in accordance with individual applications. Specific examples of the recording and reproducing media used for computers, etc. include a magnetic disk, an optical disk, a semiconductor memory, and a magnetic tape device. In particular, media for optical disk-recording and -reproducing are advantageous in terms of reduced cost per capacity due to expandability in capacity by replacement of optical disks, random accessibility, and ease of manufacture of optical disks used exclusively for reproduction.
Some people desire to use hardware employing these recording and reproducing media outdoors as well as indoors. A miniature personal computer, a PDA (Personal Digital Assistant), a handy game machine, a handy "sing along" set and an electronic still camera, for example, satisfy these demands. If the amount of information is small, a semiconductor memory is used as the data recording medium. The semiconductor memory has the merits that it is small in power consumption, immune from troubles because of no mechanism, high in data transfer rate, and the like. On the other hand, the semiconductor memory is high in cost per capacity, and accordingly, it is not suitable for a large amount of recording and reproducing.
By contrast, a hard-disk drive system in magnetic disk systems is high in data transfer rate, though lower than the semiconductor memory, and low in cost per capacity, and accordingly, it is suitable for a large amount of recording. The hard-disk drive system requires a drive mechanism for performing recording and reproducing of data with a magnetic head brought into close proximity to a hard disk, and for rotating the disk at a high speed; however, it can realize size-reduction to some extent, since there has been already developed a magnetic hard disk of 1.8 inches or 2.5 inches in diameter.